The popular type 2 diabetes drug pioglitazone may lead to moderate weight gain in some patients, but a new study finds that water retention accounts for most of the increase in body weight from using the drug. Published in the journal Diabetes Care, the study was conducted by Mayo Clinic researchers in Rochester, Minnesota. According to their results, researchers found that patients who take pioglitazone for glucose control may gain an average of three kilograms, or slightly more than six and a half pounds, in the first 12 weeks after prescription. However, 75% of the weight gain was found to consist of water retention. At the same time, pioglitazone use was also associated with reduced abdominal fat and lowered blood pressure.